Image sensors are widely used in various imaging applications and products, such as cameras, scanners, photocopiers, etc. A performance of an image sensor is depended on, among other things, its quantum efficiency and dark current.
The quantum efficiency of an image sensor indicates a number of electrons generated per number of incident photons in the image sensor. The dark current occurs when some electric current flows through the image sensor even no photons are entering the image sensor. The dark current is one of sources for noise in the image sensors.